Mitchell r



M. R. DAND.

Volute Spring.

No. 87,827. Patented March 16, 1869.

1711/: e 7115, I kieimwj 5am gaunt MITCHELL R. DAND, 0F PHILADELPHIA, PENNSYLVANIA. Letters Patent No. 87,827, dated March 16, 1869.

mrnovnn VOLU'IE SPRING.

The Schedule referred to in these Letters Patent and making part of the same.

To all wlwm it may concern Be it known that I, MITCHELL R. DAND, of the city and county of Philadelphia, and State of Pennsylvania,

.. have inventedanew and useful Improvement in Volute Springs; and I do hereby declare the following to be a full, clear, and exact description of the same sufiieient to enable others skilled in the art to which my invention appeltains, to make and use the same, reference being had to the accompanying drawings, forming part of this specification. My invention consists of a corrugated volute spring, as will be hereinafter more fully described.

In the accompanying drawings- Figure 1 is a side elevation of my improved spring.

Figure 2 is a vertical central section thereof.

' Figure 3 is a plan or top view of the plate or bar I employ in making my improved spring.

In-const-ructing my spring, I take a plate or bar of metal,of suitable dimensions, and corrugate the same in any suitable way, the corrugations running parallel with the length of the bar; or I will remark that the plate or bar may be cut from a sheet of metal which has been previously corrugated. From each end of this plate or bar, toward the centre, I cut a slit, the slits, however, terminating sufficiently far from the centre to'leave a solid central core, designated by the letter a in fig. 3.

These separated pieces I then force apart, as shown at a a. and a a; and it will be observed that the legs a a describe right angles with each other, and those,

, a a, also describe right angles with each other.

The plate or bar thus formed is very nearlyof the shape of the letter X, and in this respect it is different from the plate or bar used to form other styles of volute springs previously invented. The nearest approximation thereto is the plate used to form the quadruple volute spring, patented to Joseph Trent, on the 7th subject of my invention, it will be seen that the shape is quite diflerent, and that the spring formed of such plate (setting aside the fact that the plate is corrngated) is different from the said Trent spring, and it is also different from the spring patented to Freeland and Ward, in March, 1865, and the manner in which the coils operate (refer to fig. 1) is difi'erent; hence a spring having a diflerent mode of operation from those above referred to is obtained.

The bar or plate is coiled by any of the methods usually employed for such purpose, for instance, around a mandrel. The space occupied by the mandrel may serve as the socket for the bolt d, which unites the caps G C, as well as to steady the coils fromcrowding out laterally.

It is evident that my invention is broad enough to cover the construction of various forms of volute springs out of metal which has been corrugated in the direction of its length, whereby thinned metal may be used, and hence a great saving in material be'eifectedf I disclaim any of the parts, the subj cot-matter of the Letters Patent granted to Joseph Trent, April 4, 1868.

'Having thus described my invention, What I claim as new, and desire to secure by Letters Patent, is-

The corrugated volute spring, constructed substantially as and for the purpose described.

To the above specification of my improvement in volute springs, I have signed my name, this 8th day of January, 1869.

M. R. DAND. Witnesses:

JACOB F. HENRY, PHIL. F. LARNER. 

